The present invention relates to product checkout devices and more specifically to a triggering method for a produce recognition system.
Bar code readers are well known for their usefulness in retail checkout and inventory control. Bar code readers are capable of identifying and recording most items during a typical transaction since most items are labeled with bar codes.
Items which are typically not identified and recorded by a bar code reader are produce items, since produce items are typically not labeled with bar codes. Bar code readers may include a scale for weighing produce items to assist in determining the price of such items. But identification of produce items is still a task for the checkout operator, who must identify a produce item and then manually enter an item identification code. Operator identification methods are slow and inefficient because they typically involve a visual comparison of a produce item with pictures of produce items, or a lookup of text in table. Operator identification methods are also prone to error, on the order of fifteen percent.
A produce recognition system is disclosed in the cited co-pending application. A produce item is placed over a window in a produce data collector, the produce item is illuminated, and the spectrum of the diffuse reflected light from the produce item is measured. A terminal compares the spectrum to reference spectra in a library to determine a list of candidate identifications.
The produce recognition system triggers illumination and data capture if ambient light levels fall below a threshold. This method works well under certain lighting conditions, but may not work well under other conditions, especially darker operating conditions. Operator intervention may be required if the produce data collector does not trigger when the produce item is first placed over the window of the produce data collector.
Therefore, it would be desirable to provide a triggering method which functions under a wider range of lighting conditions without operator intervention.
In accordance with the teachings of the present invention, a triggering method for a produce recognition system is provided.
The method includes the steps of obtaining first ambient light levels from an ambient light sensor of the produce data collector with a data collection aperture covered, obtaining second ambient light levels from the ambient light sensor with the data collection aperture uncovered, determining a threshold ambient light level from the first ambient light levels and a difference between the first and second ambient light levels, obtaining a third ambient light level from the ambient light sensor with a produce item adjacent the data collection aperture, comparing the third ambient light level to the threshold ambient light level, and capturing data associated with the produce item if the third ambient light level is less than the threshold ambient light level.
It is accordingly an object of the present invention to provide a triggering method for a produce recognition system.
It is another object of the present invention to provide a triggering method for a produce recognition system which works under a wide range of lighting conditions.
It is another object of the present invention to provide a triggering method for a produce recognition system which minimizes operator intervention.
It is another object of the present invention to provide a triggering method for a produce recognition system which dynamically adjusts the triggering threshold based upon ambient light level histories.